Field of the Invention
The present invention relates generally to a part and a process of forming a part using a powder bed binding process in which a support structure for the powder bed is easily removable after the part has been fabricated.
Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Direct metal laser sintering (DMLS) is an additive manufacturing technique that uses a Yb (Ytterbium) fibre laser fired into a bed of powdered metal, aiming the laser automatically at points in space defined by a 3D model, melting or rather, welding the material together to create a solid structure.
The DMLS process involves use of a 3D CAD model to properly orient the geometry for part building and adds supports structure as appropriate. The DMLS machine uses a high-powered 200 watt Yb-fiber optic laser. Inside the build chamber area, there is a material dispensing platform and a build platform along with a recoater blade used to move new powder over the build platform. The technology fuses metal powder into a solid part by melting it locally using the focused laser beam. Parts are built up additively layer by layer, typically using layers 20 micrometers thick. This process allows for highly complex geometries to be created directly from the 3D CAD data, fully automatically, in a relatively short time and without any tooling. DMLS is a net-shape process, producing parts with high accuracy and detail resolution, good surface quality and excellent mechanical properties.
DMLS has many benefits over traditional manufacturing techniques. The ability to quickly produce a unique part is the most obvious because no special tooling is required and parts can be built in a matter of hours. Additionally, DMLS allows for more rigorous testing of prototypes. Since DMLS can use most alloys, prototypes can now be functional hardware made out of the same material as production components.
DMLS is also one of the few additive manufacturing technologies being used in production. Since the components are built layer by layer, it is possible to design internal features and passages that could not be cast or otherwise machined. Complex geometries and assemblies with multiple components can be simplified to fewer parts with a more cost effective assembly. DMLS does not require special tooling like castings, so it is convenient for short production runs.
Currently, when powder bed laser melting is employed to fabricate complex parts, a support structure (for the metal powder) must be built along with the part to ensure that the finished part conforms to the dimensions required. Since the support structure is often an impediment to the final operation of the finished part, the support structure must be removed prior to the part being functional. With some geometries the removal is not currently possible and this precludes using this fabrication technique.
The process of high energy powder bed fabrication of parts often requires the addition of support structure to the fabrication to prevent drooping or mal-forming of the structure due to lack of support in overhung areas. After placement, these supports must be removed by mechanical means prior to putting the part in service. The potential inability to remove these support structures from hidden surfaces precludes the use of this fabrication technique for some configurations thus limiting its usefulness.